金丝小枣蛋白聚糖的分离纯化及其结构分析

Isolation,purification and structure of proteoglycan from Zizyphus Jujuba cv. Jinsixiaozao

红枣作为药食同源植物,具有许多生理活性。对金丝小枣蛋白聚糖的提取纯化及其结构进行了研究。经DEAE-SepharoseCL-6B、SepharoseCL-6B和Sephadex G-200柱层析,分离纯化得白色粉末状枣蛋白聚糖(ZSG4b)。ZSG4b经高效液相色谱鉴定为均一组分,测得其分子量为1.4×105Da。化学组成分析表明,ZSG4b含83.5%多糖、9.7%蛋白质。气相层析显示ZSG4b含鼠李糖、阿拉伯糖、甘露糖、半乳糖,其摩尔比为13.8:4:3:8;氨基酸组成分析表明,ZSG4b富含天冬氨酸、谷氨酸、丝氨酸、苏氨酸、亮氨酸,它们占总氨基酸的62.8%。β-消去反应显示ZSG4b中的多糖与蛋白质由O-型糖肽键结合。

Chinese jujube（Zizyphus jujuba Miller）is a well-known oriental medicinal plant that has various biological activities.In this study, the water-soluble proteoglycan（ZSG4b） was isolated from Zizyphus jujuba cv.Jinsixiaozao. ZSG4b was obtained by purification using DEAE-SepharoseCL-6B anion exchange, Sepharose CL-6B and Sephadex G-200 column chromatography.It was eluted as a single symmetrical narrow peak on high-performance liquid chromatography（HPLC） and the average molecular weight was estimated to be 1.4 × 10^5Da. ZSG4b contained 83.5% glycan and 9.7% protein. GC analysis result showed that the glycan portion of ZSG4b was composed mainly of rhamnose,arabinose, mannose and galactose in a molar ratio of 13.8：4：3：8.The amino acid pattern showed that it was rich in aspartic acid, glutamic acid, serine,threonine and leucine; the molar content of the above five amino acids constituted 62.8% of the total amino acids.The β-elimination reaction demonstrated that the protein and glycan were linked by O-linkage.